From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.6 required=3.0 tests=DATE_IN_PAST_06_12, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 256F2C3A5A4 for ; Sat, 24 Aug 2019 06:02:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 05081233A0 for ; Sat, 24 Aug 2019 06:02:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727092AbfHXGCx (ORCPT ); Sat, 24 Aug 2019 02:02:53 -0400 Received: from mail-pf1-f194.google.com ([209.85.210.194]:36883 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727012AbfHXGCv (ORCPT ); Sat, 24 Aug 2019 02:02:51 -0400 Received: by mail-pf1-f194.google.com with SMTP id y9so7667840pfl.4 for ; Fri, 23 Aug 2019 23:02:51 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=oCd/OvNgjN1eLcHsD8e48owdFKLZIu6izSzqsYhIrYo=; b=kLRI0GoDeDqcZGlSaWWHO7hR04QWxkcqMwVTeRq/8T6+q0tK6ghHKBCQQT1+E9HMC4 goXv/SS8D2P0kXdJjslP24rIPxiKWp+v0bLnB/YMyi/Mh5jC9YWi78S6SnnJTYG2UCt8 XRT4lCGsQHBbh9uhHlm6hFKsFDMpX9hl16kSBeBVXeYbugA80NJwPkwv3LeAWvw7Y5qi djDmlO6iP0EyHsts1X3GN/dE6I+yy8pEAo/4dgCF2p8TLK4LBbPlA1lh4/uZ1gmRnead FN05IlbEAP1pniaCVl4Eh1KifsrwkVhjImQNTnAYKe5Dcrkt29QI5szszmcKC/CSButL BI4g== X-Gm-Message-State: APjAAAVUbgOxSL9K6PkctA8yr5d7VeMvzFJ6WaFNLcKC1impv/q0eT0Z wKPCrXaUaLPLP0KqX29Bss0= X-Google-Smtp-Source: APXvYqxgHWibWpCv9DU9593FwklEMZ/faA9X/VUVWe3TMQ1vbVwc5dfunNI4PBxMZzfSFjylnMjIug== X-Received: by 2002:a63:6d6:: with SMTP id 205mr7241396pgg.262.1566626570606; Fri, 23 Aug 2019 23:02:50 -0700 (PDT) Received: from sc2-haas01-esx0118.eng.vmware.com ([66.170.99.1]) by smtp.gmail.com with ESMTPSA id i11sm6505645pfk.34.2019.08.23.23.02.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 23 Aug 2019 23:02:49 -0700 (PDT) From: Nadav Amit To: Andy Lutomirski , Dave Hansen Cc: x86@kernel.org, linux-kernel@vger.kernel.org, Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Nadav Amit Subject: [PATCH v4 5/9] x86/mm/tlb: Privatize cpu_tlbstate Date: Fri, 23 Aug 2019 15:41:49 -0700 Message-Id: <20190823224153.15223-6-namit@vmware.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190823224153.15223-1-namit@vmware.com> References: <20190823224153.15223-1-namit@vmware.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org cpu_tlbstate is mostly private and only the variable is_lazy is shared. This causes some false-sharing when TLB flushes are performed. Break cpu_tlbstate intro cpu_tlbstate and cpu_tlbstate_shared, and mark each one accordingly. Cc: Andy Lutomirski Cc: Peter Zijlstra Reviewed-by: Dave Hansen Signed-off-by: Nadav Amit --- arch/x86/include/asm/tlbflush.h | 39 ++++++++++++++++++--------------- arch/x86/mm/init.c | 2 +- arch/x86/mm/tlb.c | 15 ++++++++----- 3 files changed, 31 insertions(+), 25 deletions(-) diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h index 559195f79c2f..1f88ea410ff3 100644 --- a/arch/x86/include/asm/tlbflush.h +++ b/arch/x86/include/asm/tlbflush.h @@ -178,23 +178,6 @@ struct tlb_state { u16 loaded_mm_asid; u16 next_asid; - /* - * We can be in one of several states: - * - * - Actively using an mm. Our CPU's bit will be set in - * mm_cpumask(loaded_mm) and is_lazy == false; - * - * - Not using a real mm. loaded_mm == &init_mm. Our CPU's bit - * will not be set in mm_cpumask(&init_mm) and is_lazy == false. - * - * - Lazily using a real mm. loaded_mm != &init_mm, our bit - * is set in mm_cpumask(loaded_mm), but is_lazy == true. - * We're heuristically guessing that the CR3 load we - * skipped more than makes up for the overhead added by - * lazy mode. - */ - bool is_lazy; - /* * If set we changed the page tables in such a way that we * needed an invalidation of all contexts (aka. PCIDs / ASIDs). @@ -240,7 +223,27 @@ struct tlb_state { */ struct tlb_context ctxs[TLB_NR_DYN_ASIDS]; }; -DECLARE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate); +DECLARE_PER_CPU_ALIGNED(struct tlb_state, cpu_tlbstate); + +struct tlb_state_shared { + /* + * We can be in one of several states: + * + * - Actively using an mm. Our CPU's bit will be set in + * mm_cpumask(loaded_mm) and is_lazy == false; + * + * - Not using a real mm. loaded_mm == &init_mm. Our CPU's bit + * will not be set in mm_cpumask(&init_mm) and is_lazy == false. + * + * - Lazily using a real mm. loaded_mm != &init_mm, our bit + * is set in mm_cpumask(loaded_mm), but is_lazy == true. + * We're heuristically guessing that the CR3 load we + * skipped more than makes up for the overhead added by + * lazy mode. + */ + bool is_lazy; +}; +DECLARE_PER_CPU_SHARED_ALIGNED(struct tlb_state_shared, cpu_tlbstate_shared); /* * Blindly accessing user memory from NMI context can be dangerous diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index fd10d91a6115..34027f36a944 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -951,7 +951,7 @@ void __init zone_sizes_init(void) free_area_init_nodes(max_zone_pfns); } -__visible DEFINE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate) = { +__visible DEFINE_PER_CPU_ALIGNED(struct tlb_state, cpu_tlbstate) = { .loaded_mm = &init_mm, .next_asid = 1, .cr4 = ~0UL, /* fail hard if we screw up cr4 shadow initialization */ diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index 5376a5447bd0..24c9839e3d9b 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -145,7 +145,7 @@ void leave_mm(int cpu) return; /* Warn if we're not lazy. */ - WARN_ON(!this_cpu_read(cpu_tlbstate.is_lazy)); + WARN_ON(!this_cpu_read(cpu_tlbstate_shared.is_lazy)); switch_mm(NULL, &init_mm, NULL); } @@ -277,7 +277,7 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next, { struct mm_struct *real_prev = this_cpu_read(cpu_tlbstate.loaded_mm); u16 prev_asid = this_cpu_read(cpu_tlbstate.loaded_mm_asid); - bool was_lazy = this_cpu_read(cpu_tlbstate.is_lazy); + bool was_lazy = this_cpu_read(cpu_tlbstate_shared.is_lazy); unsigned cpu = smp_processor_id(); u64 next_tlb_gen; bool need_flush; @@ -322,7 +322,7 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next, __flush_tlb_all(); } #endif - this_cpu_write(cpu_tlbstate.is_lazy, false); + this_cpu_write(cpu_tlbstate_shared.is_lazy, false); /* * The membarrier system call requires a full memory barrier and @@ -463,7 +463,7 @@ void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk) if (this_cpu_read(cpu_tlbstate.loaded_mm) == &init_mm) return; - this_cpu_write(cpu_tlbstate.is_lazy, true); + this_cpu_write(cpu_tlbstate_shared.is_lazy, true); } /* @@ -555,7 +555,7 @@ static void flush_tlb_func(void *info) VM_WARN_ON(this_cpu_read(cpu_tlbstate.ctxs[loaded_mm_asid].ctx_id) != loaded_mm->context.ctx_id); - if (this_cpu_read(cpu_tlbstate.is_lazy)) { + if (this_cpu_read(cpu_tlbstate_shared.is_lazy)) { /* * We're in lazy mode. We need to at least flush our * paging-structure cache to avoid speculatively reading @@ -655,11 +655,14 @@ static void flush_tlb_func(void *info) static bool tlb_is_not_lazy(int cpu) { - return !per_cpu(cpu_tlbstate.is_lazy, cpu); + return !per_cpu(cpu_tlbstate_shared.is_lazy, cpu); } static DEFINE_PER_CPU(cpumask_t, flush_tlb_mask); +DEFINE_PER_CPU_ALIGNED(struct tlb_state_shared, cpu_tlbstate_shared); +EXPORT_PER_CPU_SYMBOL(cpu_tlbstate_shared); + void native_flush_tlb_multi(const struct cpumask *cpumask, const struct flush_tlb_info *info) { -- 2.17.1